1. Field of the Invention
The present invention relates generally to the technical field of fire suppressant and fire preventive compositions. More particularly, the present invention relates to an inventive aqueous composition having unique properties and, most particularly, to an inventive aqueous composition more effective than water alone for fighting fires.
2. Background Information
Fire is a continuing danger to life and property worldwide. In rural areas forest, brush, and grassland fires cause immense damage each year. This destruction is not only in terms of the dollar value of timber, wildlife and livestock, but the catastrophic effects on erosion, watershed equilibrium and related problems to the natural environment. In urban areas, fire and the damage from large quantities of water used to extinguish a fire is responsible for the destruction of buildings with the loss of billions of dollars annually. Use of the composition of the present invention to replace the water used to fight fires can reduce the total water consumption by up to an order of magnitude. This reduction limits the damage caused by water in urban manufacturing facilities, and other man-made structures. Most importantly, fire is a major danger to human life. More quickly extinguishing a fire with the composition of the present invention helps reduce the loss of life to fire.
Over the years man has found numerous methods for combating fires. The use of water, foams, chemicals and other extinguishing materials are well documented. Water treated with a wetting agent has been proven to be more effective on a Class A fire where good water penetration is needed to reach and extinguish the seat of the fire. This concept is taught in U.S. Pat. No. 4,526,234 to Little. Antisettling or suspending agents are useful materials in controlling powdered flame-retardants from settling or floating. This concept is taught in U.S. Pat. No. 5,374,687 to Cooperman et al. Efforts have concentrated not only on formulations and methods for extinguishing a fire that is already in progress, but also for the prevention of fires by pretreatment of combustible surfaces. This pretreatment coating can involve man-made structures, such as buildings or storage tanks, or vegetation, such as fighting wild fires and making fire lines or fire breaks.
Currently, there have been very substantial efforts in the area of pretreatment with chemical retardants or suppressants. A number of these pretreatments have been developed and used for fighting rural forest fires. For example, antimony oxide and its complexes, borates, carbonates, bicarbonates, ammonium phosphate, ammonium sulfates, and other salts capable of being hydrated, have been demonstrated to have useful properties as firefighting chemicals. Representative prior art patents teaching the use of chemical retardants were granted in the early 1900's and continuing until more recent times. Such patents include; U.S. Pat. No. 1,030,909 to Mesturino; U.S. Pat. No. 1,339,488 to Weiss; U.S. Pat. No. 1,813,367 to Thompson; U.S. Pat. No. 2,875,044 to Dunn; U.S. Pat. Nos. 3,537,873 and 3,719,515 to Degginger; U.S. Pat. No. 4,021,464 to Mayerhoefer et al; U.S. Pat. No. 4,076,580 to Panusch et al; and U.S. Pat. No. 4,095,985 to Brown. However, although the fire inhibiting properties of the borates, carbonates and bicarbonates have been established, the use of these materials for vegetation fires has been limited because of their tendency to inhibit plant growth when used in large quantities.
Recently, attention has turned to other chemical agents, such as the synergist combination of antimony oxide and a halogen (fluorine, chlorine, bromine and iodine) or halogenated compounds. Fire retardant formulations making use of these agents are taught in U.S. Pat. No. 3,196,108 to Nelson and U.S. Pat. No. 3,936,414 to Wright et al. See also Lyons, The Chemistry and Uses of Fire Retardants, John Wiley & Sons, 1970 pages 147 and 411. Although extremely effective in this usage, the usefulness of the antimony/halogen combination is partially limited by the side reactions that may occur in a fire. Production of phosgene, diphosgene or chlorine gas (WW I chemical war gases) and the generation of corrosive agents, such as inorganic acids from ammonium phosphate and ammonium sulfate, requires the use of corrosion inhibitors to protect the firefighting pumping equipment and the aluminum of an aircraft. These corrosion inhibitors are expensive, sometimes toxic and increase the chance of environmental damage.
Another method of fighting fires is the pretreatment of flame-retardant materials on combustible surfaces that lead to the creation of intumescent coating materials. Intumescent materials expand with heat, similar to a vermiculite which expands when exposed to steam. The expanded layer then protects the original surface from heat and flame. The problem is that an expanded intumescent is also very fragile. This problem was soon realized, and the intumescent needed a protective hard outer coating. An intumescent ablative formulation answered this challenge and is taught by U.S. Pat. No. 6,716,485 B2 to Wong, et al. This lead to methods using carbonaceous materials to form a char instead of the materials being consumed by the fire. The making of carbonaceous chars is taught in many patents, including U.S. Pat. No. 6,696,030 B1 to Hayden.
In addition to all these problems, the most difficult problem to overcome for chemical retardant formulations is that they are relatively expensive, compared to water. Also of concern is the environmental impact of absorbent particles presently used in various gel formulations. The absorbent particles pose an environmental risk once used to fight a fire, particularly when used on a large scale, such as a forest fire. The cost factor also comes into conflict with applying them in large quantities, as is often required. In combating or preventing forest, brush and grass range fires, a considerable amount of effort has been spent in the search for low cost or waste materials that are both available in quantity and inexpensive. One such low cost waste material from the forest industry is lignosulfonates. Lignosulfonates are the sticking agent component in many fire retardant formulations. Teaching the use of lignosulfonates as components in fire retardant formulations include; U.S. Pat. No. 3,464,921 to Erler et al; U.S. Pat. Nos. 3,862,854 and 3,962,208 to Zeigerson et al; U.S. Pat. No. 3,915,911 to Horiguchi; U.S. Pat. No. 4,820,345 to Berg; U.S. Pat. No. 5,112,533 to Pope et al; U.S. Pat. No. 6,019,176 to Crouch and U.S. Pat. No. 6;277,296B1 to Scheffee et al.
Applicants have devised a unique composition for fighting fires. In a preferred embodiment, the composition consists of pseudo-plastic, high yield, suspending agent, plus starch, both swelled and suspended, in water. The effectiveness of the inventive composition is increased versus water alone. The composition forms a crust after making contact with a heat source. After crusting over occurs, continued heating or burning near the compositions causes the crust to turn to a carbonized char. At this point, the composition consists of an outer coat of char, which forms a hard, intumescent coating, and a soft interior of a gelled aqueous composition. This synergist combination of hard shell protecting a soft interior gel, remains in place until all the composition's water has been evaporated. The composition functions as a heat sink, maintaining a substrate temperature below 100° C.